The dataset used for illustration is derived from NYC restaurant violation results. It describes the percentage of A, B, C graded restaurants by zip code in a given year. This was derived from individual restaurant data within each zip code. Details for each column are as follows:
Year - Inspection Year
ZipCode - NYC Zip code
Aprop - Proportion of A grade restaurant counts in a zip code for given year
Bprops - Proportion of B grade restaurant counts in a zip code for given year
Cprops - Proportion of C grade restaurant counts in a zip code for given year
Filter the dataset by dragging “year” column from dimensions to filter. Click on the drop down and edit filters.
Add zip code to marks and you should see a map. Tableau automatically detects this as geographical column, but you can verify this by using drop downs as below.
After you add this as marks, it will appear as a label. For plotting on map, convert this to a dimension and continuous as shown in drop down.
Change the type of projection of Aprop on map to color by clicking on the label (just before Aprop as shown).
You can change the color palette by editing colors. If your data is discrete, you can specify the number of steps, and charge the color palette using a simple drop down.